The central nervous system has been postulated to have a direct influence over aqueous humor dynamics. Stimulation of certain regions of the hypothalamus and injections of osmotic agents into the third ventricle resulted in alterations of intraocular pressure. Unilateral optic nerve transection has been associated with a reduced intraocular pressure response to systemically administered osmotic agents and centrally acting drugs. The objectives of the present research are to further define the routes and mechanisms of action of the central control of intraocular pressure. Rabbits and monkeys will be studied incorporating the unilateral transected optic nerve and third ventricle cannula models with hypothalamic stimulation. Stereotactic methods will be utilized to study the effects of electrical and microinjection stimulation on intraocular pressure as well as systemic blood pressure. Electrical destruction will be performed of hypothalamic areas which result in pure intraocular pressure responses. Hypothalamic localization will be sought by examining the neuropathology of the stereotactically induced lesions and by generation studies with special status.